Ear development and formation of grain yield in winter wheat.

The pattern of grain production of a winter wheat crop and the effect of plant density and time of tiller emergence on grain yield/ear were studied. At harvest, ear size and ear components were ascertained and were discussed in relation to ear growth and ear development during the prefloral and postfloral growing period. Detailed information was obtained on the productivity of ear-bearing tillers and their contribution to final grain yield. Shoot productivity decreased in denser crops; ears were smaller because spikelet differentiation, grain set and grain filling were inadequate. The date that the tiller emerged largely determined its subsequent grain yield. With later tiller initiation and emergence fewer ears were produced. Moreover, these ears were smaller because spikelet initiation, spikelet differentiation, grain set and grain filling were reduced. At low and moderate plant densities, the grain yield of the early-emerged tillers only slightly lagged behind that of main shoots and max. grain yield could be achieved at moderate plant densities. It was concluded that in cereal farming, high and stable grain yields are aims to be achieved. These can be best achieved by having moderate plant densities and applying correct treatments for good crop growth. (Abstract retrieved from CAB Abstracts by CABI’s permission

Ear formation and grain yield of winter wheat as affected by time of nitrogen supply.

Winter wheat cv. Caribo (1979) or Arminda and Okapi (1980) was provided with an additional N dressing at different stages between tillering and ear emergence after a basal N dose applied at the onset of tillering. The effect of N on ear formation depended greatly on the growth stage at the time of N application. Max. effects on tiller formation and spikelet initiation were achieved when additional N was supplied at the beginning of tillering; on ear number when N was supplied at the onset of stem elongation; on the numbers of fertile spikelets, grains/fertile spikelet and grains/ear when N was applied during stem elongation until flag leaf emergence and on single grain wt. when N was applied at ear emergence. Variations in 1000-grain wt. were small, therefore grain yield/ear as well as yield/unit area was largely determined by grain number. Main shoots outyielded ear-bearing tillers because of a higher grain number. In ear-bearing tillers, grain yield largely depended on grain number, being highest in the older tillers. Grain formation of ear-bearing tillers was more strongly affected by the time of additional N application than that of main shoots. Top-dressings of N applied during stem elongation increased the grain number of ear-bearing tillers considerably, because both the number of fertile spikelets and the grain number/fertile spikelet were higher. In the young late-appeared tillers, the opt. time to apply additional N for grain set shifted to later stages of development. (Abstract retrieved from CAB Abstracts by CABI’s permission

Yield responses of winter wheat to plant removal and to wheelings.

In winter wheat cv. Arminda the removal of plants from 2 adjacent rows increased grain yields in 2 rows on either side of the path thus created. This yield compensation was achieved by an increase in ear number/plant, grain number/ear and 1000-grain weight. Yield compensation exceeded 80% if the plants had been removed at an early growth stage (GS); the yield compensation was smaller the later the plants were removed, being 14% after plants had been removed at Zadoks GS 71. The contribution of grain number/ear to yield compensation followed a similar trend to ear number with hardly any effect when plants were removed after GS 51 and GS 32, resp. Frequent passes through the crop with a tractor led to almost total failure of grain production in the wheelings created, but this yield loss was partly compensated for by the increased yields of the rows next to the tracks. When tramlines were used for carrying out the cultural operations, the yield compensation by plants in bordering rows was greater, and consequently the yield loss was smaller. It is estimated that in commercial wheat production the yield losses resulting from cultural operations will be small, usually less than 150 kg grain/ha. (Abstract retrieved from CAB Abstracts by CABI’s permission

Zwavelvoorziening vraagt toenemende aandacht

Door verminderde industriële depositie van zwavel en minder verontreinigde meststoffen kan de zwavelvoorziening van landbouwgewassen in gevaar komen., met name op lichte gronden. PPO onderzocht in bemestingsproeven met wintertarwe in verschillende regio's en op verschillende grondsoorten het effect van zwavelbemesting op de zwavelopname en het zwavelgehalte in verschillende groeistadia en de uiteindelijke korrelopbrengst. Voor een goede stikstofvoorziening zijn vooral zwavelhoudende stikstofmeststoffen gunstig die bij het begin van de groei van het gewas worden gegeve

Effect of sowing date and seed rate on crop development and grain production of winter wheat.

In a field trial in 1973-5, winter wheat cv. Lely was sown on 3 dates at 3- to 4-wk intervals from end-Sept. at low (80-90 kg seed/ha) or high (160-180 kg seed/ha) sowing rates. Delaying the sowing date decreased grain yield. This decrease was caused by a smaller number of grains/ear and a lower grain wt. Sowing rate had a positive influence on the number of ears, but a negative effect on the number of grains/ear and the grain wt. With early sowing, sowing rate was found to have no effect on grain yield, due to mutual compensation of changes in yield components. With late sowing, a higher sowing rate increased the number of ears so much that a higher grain yield was achieved. The grain yield/ear depended on the age of the tiller. Tillers that emerged earlier produced more and heavier ears. The number of grains/ear and the grain wt. could be related to the rate of development of the ear-bearing shoot. The pattern of tillering was affected by the sowing date. With early sowing, most tillers emerged in autumn and winter, whereas the late-sown wheat tillered in spring. Also, the early-sown crop consisted largely of ears from early tillers, whereas the late-sown one had many ears from late-formed tillers. (Abstract retrieved from CAB Abstracts by CABI’s permission

Teelt van kwaliteitsrassen van wintertarweGrowing winter wheat for quality in the Netherlands

Rassenonderzoek naar eiwitgehalte en invloed van stikstofbemesting op de kwalitei